Method of Transmitting a Wideband Frame

1. A method of transmitting a wideband frame in a wideband system having backward compatibility with a narrowband system, the method comprising: configuring, by a base station, a wideband carrier from a set of base carriers, wherein a bandwidth of any one of the base carriers corresponds to a bandwidth of a narrowband carrier for the narrowband system, and wherein a center frequency of the any one of the base carriers is equal to a center frequency of the narrowband carrier; allocating, by the base station, a traffic channel to the wideband carrier; and transmitting, by the base station, information on the wideband carrier, wherein the wideband carrier carries first data for a first user equipment (UE), wherein the narrowband carrier carries second data for a second UE, the second UE being different from the first UE, wherein each of the base carriers comprises guard subcarriers and traffic subcarriers, and wherein, when the wideband carrier is simultaneously transmitted with the narrowband carrier in a specific time duration, first guard subcarriers, located in the wideband carrier and adjacent to the narrowband carrier, are allocated for a traffic channel for the first UE in the specific time duration, and second guard subcarriers, located in the narrowband carrier, are not allocated for a traffic channel for the second UE in the specific time duration.

2. The method of claim 1 , wherein the wideband carrier comprises a first base carrier, a second base carrier and a third base carrier contiguous in the frequency domain, and wherein the narrowband carrier is identical to the second base carrier.

3. The method of claim 1 , wherein a bandwidth of each of the base carriers is equal to a bandwidth of the narrowband carrier.

4. The method of claim 1 , wherein a center frequency spacing between two adjacent base carriers of the wideband carrier is an integer multiple of a subcarrier spacing.

5. The method of claim 1 , wherein, when only one base carrier of the base carriers is used, at least one of the first guard subcarriers and the second guard subcarriers are not used.

6. A base station configured to transmit a wideband frame in a wideband system having backward compatibility with a narrowband system, the base station comprising: a processor configured to configure a wideband carrier from a set of base carriers, wherein a bandwidth of any one of the base carriers corresponds to a bandwidth of a narrowband carrier for the narrowband system, and wherein a center frequency of the any one of the base carriers is equal to a center frequency of the narrowband carrier, allocate a traffic channel to the wideband carrier, and transmit information on the wideband carrier, wherein the wideband carrier carries first data for a first user equipment (UE), wherein the narrowband carrier carries second data for a second UE, the second UE being different from the first UE, wherein each of the base carriers comprises guard subcarriers and traffic subcarriers, and wherein, when the wideband carrier is simultaneously transmitted with the narrowband carrier in a specific time duration, first guard subcarriers, located in the wideband carrier and adjacent to the narrowband carrier, are allocated for a traffic channel for the first UE in the specific time duration, and second guard subcarriers, located in the narrowband carrier, are not allocated for a traffic channel for the second UE in the specific time duration.